Aqueous primary dispersions and coating matters, a method for producing same and the use thereof

ABSTRACT

Aqueous primary dispersions and coating materials comprising dispersed and/or emulsified, solid and/or liquid polymer particles and/or dispersed solid core shell particles having a diameter≦500 nm preparable by controlled free-radical microemulsion or miniemulsion polymerization of A) at least one olefinically unsaturated monomer and B) at least one olefinically unsaturated monomer which is different than the olefinically unsaturated monomer (A) and has the general formula I: R 1 R 2 C═CR 3 R 4  (I), in which the radicals R 1 , R 2 , R 3  and R 4  independently of one another are hydrogen atoms or substituted or unsubstituted alkyl, cycloalkyl, alkylcycloalkyl, cycloalkylalkyl, aryl, alkylaryl, cycloalkylaryl, arylalkyl or arylcycloalkyl radicals, with the proviso that at least two of the variables R 1 , R 2 , R 3  and R 4  are substituted or unsubstituted aryl, arylalkyl or arylcycloalkyl radicals, especially substituted or unsubstituted aryl radicals; and in the presence of (C) at least one hydrophobic cross-linking agent for the copolymer resulting from the starting products (A) and (B).

This application is a National Phase Application of PCT/EP00/11006 filedon 8 Nov. 2000.

The present invention relates to novel aqueous primary dispersions andcoating materials which comprise dispersed and/or emulsified, solidand/or liquid polymer particles and/or dispersed solid core-shellparticles having a diameter≦500 nm. The present invention furtherrelates to a novel process for preparing the novel aqueous primarydispersions and coating materials by means of controlled free-radicalmicroemulsion and miniemulsion polymerization. The present inventionrelates, furthermore, to the use of the novel aqueous primarydispersions and coating materials for producing single-coat or multicoatclearcoat systems and single-coat or multicoat color and/or effect paintsystems in automotive OEM finishing and refinishing, industrial coating,including container coating, coil coating and the coating of electricalcomponents, and furniture coating.

Microemulsions and miniemulsions are dispersions comprising water, anoil phase and one or more surface-active substances and having dropletsizes of from 5 to 50 nm (microemulsions) or from 50 to 500 nm.

Microemulsions are regarded as being thermodynamically stable, whereasthe miniemulsions are regarded as metastable (cf. EmulsionPolymerization and Emulsion Polymers, Editors: P. A. Lovell and MohamedS. El-Aasser, John Wiley and Sons, Chichester, N.Y., Weinheim, 1997,pages 700 et seq.; Mohamed S. El-Aasser, Advances in EmulsionPolymerization and Latex Technology, 30th Annual Short Course, Volume 3,Jun. 7-11, 1999, Emulsion Polymers Institute, Lehigh University,Bethlehem, Pa., USA). Both types of dispersions find broad applicationin the art: for example, in cleaning products, cosmetics or bodycareproducts. They may, however, also be used for polymerization reactionsin place of the customary macroemulsions, in which droplet sizes>1000 nmare present.

It would be desirable here to carry out the free-radical polymerizationin microemulsion and miniemulsion by the so-called batch procedure,where the total amount of the monomers is introduced as initial chargein an aqueous medium, emulsified and subsequently polymerized tocompletion. This would make it possible to avoid from the outset theproblems which result from the feed technique. These problems consist inparticular in a comparatively high level of expenditure on measurementand control equipment and on apparatus, and in the fact that themonomers being fed in do not arrive at the site of polymerization butinstead, as with macroemulsion polymerization, serve as a monomerreservoir for the initiated monomer droplets. As a result, thesedroplets change their composition continuously, which in the case oftheir subsequent initiation can lead to nonuniformity in the compositionof the resultant polymer particles.

The preparation of aqueous primary dispersions by means of free-radicalminiemulsion polymerization is known, for example, from theinternational patent application WO 98/02466 or from German patentsDE-A-196 28 143 and DE-A-196 28 142. In the case of these knownprocesses, the monomers may be copolymerized in the presence ofdifferent low molecular mass, oligomeric or polymeric, hydrophobicsubstances. Furthermore, hydrophobic, organic auxiliaries of lowsolubility in water, such as plasticizers, enhancers of the tackiness ofthe resulting film, film-forming auxiliaries or other, unspecifiedorganic additives, may be incorporated into the monomer droplets of theminiemulsion. The use of diphenylethylene as a comonomer and ofhydrophobic crosslinking agents for the copolymers formed from themonomers, and the use of the known aqueous primary dispersions forpreparing coating materials, are equally not evident from theabovementioned patents. Although the known processes solve the problemof the exothermic nature of the free-radical polymerization andcopolymerization to a certain extent, they do so at the expense of anincreased level of measurement and control equipment.

Aqueous coating materials based on aqueous primary dispersions whichcomprise solid core-shell particles and have been prepared byminiemulsion polymerization of monomers in the presence of hydrophobicpolymers are known from the patents EP-A-0 401 565, WO 97/49739 orEP-A-0 755 946. The use of a diphenylethylene comonomer andcopolymerization in the presence of hydrophobic crosslinking agents forthe copolymers formed from the monomers are not disclosed by thesepatents. Although the known coating materials already have numerousadvantageous properties, there is still the occurrence of problemsassociated with inadequate distribution of the crosslinking agents inthe aqueous dispersions. One particular consequence of this is that alarger amount of crosslinking agents has to be used than would betheoretically necessary. Unreacted crosslinking agents may then, incertain circumstances, be harmful to the performance properties of thecoatings produced from the coating materials.

The microencapsulation of hydrophobic organic solvents or of targetmaterials such as biocides and herbicides in water-insoluble core-shellparticles produced by miniemulsion polymerization is known from thepatents EP-A-0 203 724 or U.S. Pat. No. 4,677,003. However,copolymerization is not conducted in the presence of hydrophobiccrosslinking agents for the copolymers formed from the monomers. Nor isthe use of a diphenylethylene comonomer described.

The patents EP-A-0 622 389 or DE-A-43 14 297 disclose thecopolymerization of monomers in the presence of blocked polyisocyanatesand epoxy resins. However, the technique employed is not that ofminiemulsion polymerization. A comparable process, but in which thecrosslinking agents are not specified, is disclosed by the patentsEP-A-0 758 347 or WO 95/29944. The corresponding known copolymers andtheir primary dispersions are used for preparing coating materials. Theknown coating materials likewise have the problems associated withinsufficiently fine distribution of the crosslinking agents in thecoating materials.

The free-radical addition polymerization employed to prepare acrylatecopolymers is frequently very exothermic and difficult to control. Whatthis means for the reaction regime is that high concentrations ofmonomers and/or the so-called batch procedure, where the total amount ofthe monomers is introduced as initial charge in an aqueous medium,emulsified and subsequently polymerized to completion, must be avoided.In addition, the targeted establishment of defined molecular weights,molecular weight distributions and other properties often causesdifficulties. The targeted establishment of a defined profile ofproperties in acrylate copolymers is, however, of great importance fortheir use as binders in coating materials, especially aqueous coatingmaterials, since by this means it is possible to exert direct influenceon the performance properties profile of the coating materials.

There has therefore been no lack of attempts to regulate thefree-radical copolymerization of olefinically unsaturated monomers in atargeted way.

For instance, the international patent application WO 98/01478 describesa process in which the copolymerization is conducted in the presence ofa free-radical initiator and of a thiocarbonylthio compound as chaintransfer agent.

The international patent application WO 92/13903 describes a process forpreparing copolymers of low molecular weight by free-radical chainpolymerization in the presence of a group transfer agent having acarbon-sulfur double bond. These compounds act not only as chaintransfer agents but also as growth regulators, and so result only incopolymers of low molecular weight.

The international patent application WO 96/15157 discloses a process forpreparing copolymers having a comparatively narrow molecular weightdistribution, in which a monomer is reacted with a vinyl-terminatedmacromonomer in the presence of a free-radical initiator.

Furthermore, the international patent application WO 98/37104 disclosesthe preparation of acrylate copolymers having defined molecular weightsby free-radical polymerization in the presence of a chain transfer agenthaving a C—C double bond and having radicals which activate this doublebond in respect of the free-radical addition of monomers.

Despite significant progress in this field, there continues to be a lackof a universally applicable process of controlled free-radicalpolymerization which yields chemically structured polymers, especiallyacrylate copolymers, in a simple manner and by means of which it ispossible to tailor the profile of properties of the polymers in respectof their application in coating materials, especially aqueous coatingmaterials, which are used to produce clearcoats and multicoat colorand/or effect paint systems.

It is an object of the present invention to find new aqueous primarydispersions and coating materials comprising dispersed and/oremulsified, solid and/or liquid polymer particles and/or dispersed solidcore-shell particles having a diameter≦500 nm which no longer have thedisadvantages of the prior art but instead can be prepared in a simpleand controlled manner. The copolymers present in the new aqueous primarydispersions and coating materials ought to have defined molecularweights and ought to be preparable inter alia by the batch procedurewithout the occurrence in this case of the problems associated with thehighly exothermic nature of the free-radical polymerization, ranging forinstance from the thermal damaging of the products through to runaway ofthe reactor. Moreover, the new aqueous primary dispersions and coatingmaterials ought to contain very finely distributed crosslinking agents.

A further object of the present invention was to find a new process forpreparing aqueous primary dispersions and coating materials byfree-radical microemulsion or miniemulsion polymerization which nolonger has the disadvantages of the prior art, but can instead becarried out by the batch procedure without the problems described aboveoccurring, and which allows the profile of properties of the resultingcopolymers to be adjusted in a targeted way, especially in terms of themolecular weight and molecular weight distribution.

Accordingly, we have found the novel aqueous primary dispersions andcoating materials comprising dispersed and/or emulsified, solid and/orliquid polymer particles and/or dispersed solid core-shell particleshaving a diameter≦500 nm, preparable by controlled free-radicalmicroemulsion or miniemulsion polymerization of

-   -   A) at least one olefinically unsaturated monomer and    -   B) at least one olefinically unsaturated monomer which is        different than the olefinically unsaturated monomer (A) and has        the general formula I        R¹R²C═CR³R⁴  (I)        in which the radicals R¹, R², R³ and R⁴ each independently of        one another are hydrogen atoms or substituted or unsubstituted        alkyl, cycloalkyl, alkylcycloalkyl, cycloalkylalkyl, aryl,        alkylaryl, cycloalkylaryl arylalkyl or arylcycloalkyl radicals,        with the proviso that at least two of the variables R¹, R², R³        and R⁴ are substituted or unsubstituted aryl, arylalkyl or        arylcycloalkyl radicals, especially substituted or unsubstituted        aryl radicals;        in the presence of at least    -   C) at least one hydrophobic crosslinking agent for the copolymer        resulting from the starting products (A) and (B),        which are referred to below for short as “primary dispersions of        the invention” and, respectively, “coating materials of the        invention”.

We have also found the novel process for preparing aqueous primarydispersions and coating materials comprising dispersed and/oremulsified, solid and/or liquid polymer particles and/or dispersed solidcore-shell particles having a diameter≦500 nm by controlled free-radicalmicroemulsion or miniemulsion polymerization of

-   -   A) at least one olefinically unsaturated monomer and    -   B) at least one olefinically unsaturated monomer which is        different than the olefinically unsaturated monomer (A) and has        the general formula I        R¹R²C═CR³R⁴  (I)        in which the radicals R¹, R², R³ and R⁴ each independently of        one another are hydrogen atoms or substituted or unsubstituted        alkyl, cycloalkyl, alkylcycloalkyl, cycloalkylalkyl, aryl,        alkylaryl, cycloalkylaryl arylalkyl or arylcycloalkyl radicals,        with the proviso that at least two of the variables R¹, R², R³        and R⁴ are substituted or unsubstituted aryl, arylalkyl or        arylcycloalkyl radicals, especially substituted or unsubstituted        aryl radicals;        in the presence of at least    -   C) at least one hydrophobic crosslinking agent for the copolymer        resulting from the starting products (A) and (B),        which is referred to for short below as “process of the        invention”.

Further subjects of the invention will emerge from the followingdescription.

In the light of the prior art it was surprising and unforeseeable by theskilled worker that the object on which the present invention was basedcould be achieved through the primary dispersions of the invention andthe coating materials of the invention and also through the process ofthe invention. In particular, it was surprising that the copolymerspresent in the primary dispersions of the invention had properties whichmake them highly suitable for use in coating materials. It was alsosurprising that the primary dispersions of the invention can be useddirectly as coating materials, even needing less crosslinking agent thanconventional coating materials. Not least, it was surprising that theprocess of the invention yields the primary dispersions and coatingmaterials of the invention in a particularly simple and targeted mannerwithout the occurrence of the above-described problems known from theprior art.

For the purposes of the present invention, the property of beinghydrophilic is understood as the constitutional property of a moleculeor functional group to penetrate into the aqueous phase or to remaintherein. Accordingly, for the purposes of the present invention, theproperty of being hydrophobic is understood as the constitutionalproperty of a molecule or functional group to exhibit exophilic behaviorwith respect to water; i.e., they display the tendency not to penetrateinto water, or to depart the aqueous phase. For further details,reference is made to Römpp Lexikon Lacke und Druckfarben, Georg ThiemeVerlag, Stuttgart, N.Y., 1998, “Hydrophilicity”, “Hydrophobicity”, pages294 and 295.

In accordance with the invention, the primary dispersions and coatingmaterials comprise dispersed and/or emulsified solid and/or liquidpolymer particles and/or dispersed solid core-shell particles. The sizeof the polymer particles or of the dispersed core-shell particles is adirect result of the process of the invention described below. In thiscase the average particle diameter is less than 500 nm. It is preferablyfrom 10 to 500 nm, more preferably from 50 to 400 nm, and with veryparticular preference from 100 to 350 nm.

The primary dispersions and coating materials of the invention have anadvantageously high solids content of, for example, more than 20% byweight, preferably more than 30% by weight. It is even possible toobtain solids contents of more than 40% by weight. The primarydispersions and coating materials of the invention have a low viscosity,even at high solids content.

The core-shell particles for use in accordance with the invention resultfrom the graft copolymerization of organic solids and the comonomers (A)and (B) for use in accordance with the invention, described below. Saidorganic solids are preferably hydrophobic polymers, as described, forexample, in the patents EP-A-0 401 565, page 3, line 5 to page 4, line50, WO 97/49739, page 4, line 19 to page 5, line 3, or EP-A-0 755 946,page 3, line 26 to page 5, line 38. These hydrophobic polymers may alsobe prepared by the process of the invention.

The primary dispersions and coating materials of the invention may alsohave a bimodal particle size distribution in which from 0.1 to 80% byweight, in particular from 1.0 to 50% by weight, of the copolymerresulting from the comonomers (A) and (B) have a particle size,determined using an analytical ultracentrifuge, of from 20 to 500 nm, inparticular from 50 to 300 nm, and from 20 to 99.9% by weight, inparticular from 50 to 99% by weight, of the copolymer have a particlesize of from 200 to 1500 nm, in particular from 300 to 900 nm, saidparticle sizes differing by at least 50 nm, in particular by at least100 nm, with very particular preference by at least 200 nm. Concerningthe measurement method, reference is made for further details to lines 5to 9 of page 6 of the German patent application DE-A-196 28 142.

The first starting compound essential to the invention for the primarydispersions or coating materials of the invention, and for the processof the invention, is at least one olefinically unsaturated monomer (A).

It is preferred here to use at least one monomer (A) comprising reactivefunctional groups which are able to enter into crosslinking reactionswith the complementary reactive functional groups of the crosslinkingagents (C). Examples of suitable complementary reactive functionalgroups for use in accordance with the invention are collated in theoverview below. In the overview, the variable R is an acyclic or cyclicaliphatic radical, an aromatic radical and/or an aromatic-aliphatic(araliphatic) radical; the variables R′ and R″ are identical ordifferent aliphatic radicals or are linked to one another to form analiphatic or heteroaliphatic ring.

Overview: Examples of Complementary Functional Groups

Monomer (A) and crosslinking agent (C) or Crosslinking agent (C) andmonomer (A) —SH —C(O)—OH —NH₂ —C(O)—O—C(O)— —OH —NCO —O—(CO)—NH—(CO)—NH₂—NH—C(O)—OR —O—(CO)—NH₂ —CH₂—OH >NH —CH₂—O—CH₃ —NH—C(O)—CH(—C(O)- OR)₂—NH—C(O)—CH(—C(O)- OR)(—C(O)—R) —NH—C(O) —NR′R″ =Si(OR)₂

—C(O)—OH

The selection of the respective complementary groups is guided on theone hand by the consideration that, during the storage of primarydispersions or coating materials of the invention, these groups do notenter into any unwanted reactions and/or, if appropriate, do not inhibitor disrupt curing with actinic radiation, and on the other hand by thetemperature range within which crosslinking is to take place.

For the coating materials of the invention it is preferred to employcrosslinking temperatures of from 100° C. to 180° C. It is thereforepreferred to use monomers (A) containing thio, hydroxyl,alkoxymethylamino, imino, carbamate, allophanate and/or carboxyl groups,but in particular amino, alkoxymethylamino or hydroxyl groups,especially hydroxyl groups, on the one hand, and crosslinking agents (C)containing anhydride, carboxyl, epoxy, blocked isocyanate, urethane,methylol, methylol ether, siloxane, amino, hydroxyl and/orbeta-hydroxyalkylamide groups, but especially blocked isocyanate,urethane or methylol ether groups, on the other.

Examples of Suitable Monomers (A) are

-   a1) substantially acid-group-free (meth)acrylic esters such as    (meth)acrylic alkyl or cycloalkyl esters having up to 20 carbon    atoms in the alkyl radical, especially methyl, ethyl, propyl,    n-butyl, sec-butyl, tert-butyl, hexyl, ethylhexyl, stearyl and    lauryl acrylate or methacrylate; cycloaliphatic (meth)acrylic    esters, especially cyclohexyl, isobornyl, dicyclopentadienyl,    octahydro-4,7-methano-1H-indenemethanol (meth)acrylate or    tert-butylcyclohexyl (meth)acrylate; (meth)acrylic oxaalkyl esters    or oxacycloalkyl esters such as ethyltriglycol (meth)acrylate and    methoxyoligoglycol (meth)acrylate having a molecular weight Mn of    preferably 550, or other ethoxylated and/or propoxylated    hydroxyl-free (meth)acrylic acid derivatives. These may contain    minor amounts of (meth)acrylic alkyl or cycloalkyl esters of higher    functionality, such as the di(meth)acrylates of ethylene glycol,    propylene glycol, diethylene glycol, dipropylene glycol, butylene    glycol, 1,5-pentanediol, 1,6-hexanediol,    octahydro-4,7-methano-1H-indenedimethanol or 1,2-, 1,3- or    1,4-cyclohexanediol; trimethylolpropane di- or tri(meth)acrylate; or    pentaerythritol di-, tri- or tetra(meth)acrylate. For the purposes    of the present invention, minor amounts of monomers of higher    functionality in this case are to be understood as amounts which do    not lead to crosslinking or gelling of the copolymers (A).-   a2) Monomers which carry per molecule at least one hydroxyl, amino,    alkoxymethylamino or imino group and are substantially free from    acid groups, such as hydroxyalkyl esters of acrylic acid,    methacrylic acid or another alpha,beta-olefinically unsaturated    carboxylic acid, which derive from an alkylene glycol esterified    with the acid, or which are obtainable by reacting the    alpha,beta-olefinically unsaturated carboxylic acid with an alkylene    oxide, especially hydroxyalkyl esters of acrylic acid, methacrylic    acid, ethacrylic acid, crotonic acid, maleic acid, fumaric acid or    itaconic acid in which the hydroxyalkyl group contains up to 20    carbon atoms, such as 2-hydroxyethyl, 2-hydroxypropyl,    3-hydroxypropyl, 3-hydroxybutyl, 4-hydroxybutyl acrylate,    methacrylate, ethacrylate, crotonate, maleate, fumarate or    itaconate; or hydroxycycloalkyl esters such as    1,4-bis(hydroxymethyl)cyclohexane,    octahydro-4,7-methano-1H-indenedimethanol or methylpropanediol    monoacrylate, monomethacrylate, monoethacrylate, monocrotonate,    monomaleate, monofumarate or monoitaconate; or reaction products of    cyclic esters, such as epsilon-caprolactone, for example, and these    hydroxyalkyl or hydroxycycloalkyl esters; or olefinically    unsaturated alcohols such as allyl alcohol or polyols such as    trimethylolpropane monoallyl or diallyl ether or pentaerythritol    monoallyl, diallyl or triallyl ether (as far as these monomers (a2)    of higher functionality are concerned, the comments made above    relating to the monomers (a1) of higher functionality apply    analogously); N,N-dimethylaminoethyl acrylate, N,N-diethylaminoethyl    methacrylate, allylamine or N-methyliminoethyl acrylate or    N,N-di(methoxymethyl)aminoethyl acrylate and methacrylate or    N,N-di(butoxymethyl)aminopropyl acrylate and methacrylate;-   a3) monomers which carry per molecule at least one acid group which    can be converted into the corresponding acid anion group, such as    acrylic acid, methacrylic acid, ethacrylic acid, crotonic acid,    maleic acid, fumaric acid or itaconic acid; olefinically unsaturated    sulfonic or phosphonic acids or their partial esters; or    mono(meth)acryloyloxyethyl maleate, succinate or phthalate. For the    purposes of the present invention the monomers (a3) are not used as    the sole monomers (A) but are always used in conjunction with other    monomers (A) and, moreover, in amounts so small that the monomers    (a3) do not polymerize outside the droplets of the miniemulsion.-   a4) Vinyl esters of alpha-branched monocarboxylic acids having 5 to    18 carbon atoms in the molecule. The branched monocarboxylic acids    can be obtained by reacting formic acid or carbon monoxide and water    with olefins in the presence of a liquid, strongly acidic catalyst;    the olefins may be cracking products of paraffinic hydrocarbons,    such as mineral oil fractions, and may comprise both branched and    straight-chain acyclic and/or cycloaliphatic olefins. The reaction    of such olefins with formic acid or, respectively, with carbon    monoxide and water produces a mixture of carboxylic acids in which    the carboxyl groups are located predominantly on a quaternary carbon    atom. Examples of other olefinic starting materials are propylene    trimer, propylene tetramer and diisobutylene. Alternatively, the    vinyl esters (a4) may be prepared in conventional manner from the    acids, by reacting, for example, the acid with acetylene. Particular    preference, owing to their ready availability, is given to using    vinyl esters of saturated aliphatic monocarboxylic acids having 9 to    11 carbon atoms that are branched on the alpha carbon atom, but    especially Versatic® acids.-   a5) Reaction products of acrylic acid and/or methacrylic acid with    the glycidyl ester of an alpha-branched monocarboxylic acid having    from 5 to 18 carbon atoms per molecule, in particular a Versatic®    acid, or, instead of the reaction product, an equivalent amount of    acrylic and/or methacrylic acid which is then reacted during or    after the polymerization reaction with the glycidyl ester of an    alpha-branched monocarboxylic acid having 5 to 18 carbon atoms per    molecule, especially a Versatic® acid.-   a6) Cyclic and/or acyclic olefins such as ethylene, propylene,    1-butene, 1-pentene, 1-hexene, cyclohexene, cyclopentene,    norbornene, butadiene, isoprene, cyclopentadiene and/or    dicyclopentadiene.-   a7) (Meth)acrylamides such as (meth)acrylamide, N-methyl-,    N,N-dimethyl-, N-ethyl-, N,N-diethyl-, N-propyl-, N,N-dipropyl-,    N-butyl-, N,N-dibutyl-, N-cyclohexyl-, N,N-cyclohexylmethyl- and/or    N-methylol-, N,N-dimethylol-, N-methoxymethyl-,    N,N-di(methoxymethyl)-, N-ethoxymethyl- and/or    N,N-di(ethoxyethyl)-(meth)acrylamide;-   a8) monomers containing epoxide groups, such as the glycidyl ester    of acrylic acid, methacrylic acid, ethacrylic acid, crotonic acid,    maleic acid, fumaric acid and/or itaconic acid.-   a9) Vinylaromatic hydrocarbons such as styrene, alpha-alkylstyrenes,    especially alpha-methylstyrene, and/or vinyltoluene; vinylbenzoic    acid (all isomers), N,N-diethylaminostyrene (all isomers),    alpha-methylvinylbenzoic acid (all isomers),    N,N-diethylamino-alpha-methylstyrene (all isomers) and/or    p-vinylbenzenesulfonic acid.-   a10) Nitriles such as acrylonitrile and/or methacrylonitrile.-   a11) Vinyl compounds, especially vinyl halides and/or vinylidene    dihalides such as vinyl chloride, vinyl fluoride, vinylidene    dichloride or vinylidene difluoride; N-vinylamides such as    vinyl-N-methylformamide, N-vinylcaprolactam, 1-vinylimidazole or    N-vinylpyrrolidone; vinyl ethers such as ethyl vinyl ether, n-propyl    vinyl ether, isopropyl vinyl ether, n-butyl vinyl ether, isobutyl    vinyl ether and/or vinyl cyclohexyl ether; and/or vinyl esters such    as vinyl acetate, vinyl propionate, vinyl butyrate, vinyl pivalate    and/or the vinyl ester of 2-methyl-2-ethylheptanoic acid.-   a12) Allyl compounds, especially allyl ethers and allyl esters such    as allyl methyl, ethyl, propyl or butyl ether or allyl acetate,    propionate or butyrate.-   a13) Polysiloxane macromonomers having a number-average molecular    weight Mn of from 1000 to 40,000 and having on average from 0.5 to    2.5 ethylenically unsaturated double bonds per molecule; especially    polysiloxane macromonomers having a number-average molecular weight    Mn of from 2000 to 20,000, with particular preference from 2500 to    10,000 and, in particular, from 3000 to 7000 and having on average    from 0.5 to 2.5, preferably from 0.5 to 1.5, ethylenically    unsaturated double bonds per molecule, as are described in DE-A-38    07 571 on pages 5 to 7, in DE-A-37 06 095 in columns 3 to 7, in    EP-B-0 358 153 on pages 3 to 6, in U.S. Pat. No. 4,754,014 in    columns 5 to 9, in DE-A-44 201 823 or in the international patent    application WO 92/22615 on page 12, line 18 to page 18, line 10.    and/or-   a14) Acryloyloxysilane-containing vinyl monomers, preparable by    reacting hydroxy-functional silanes with epichlorohydrin and then    reacting the reaction product with (meth)acrylic acid and/or    hydroxyalkyl and/or hydroxycycloalkyl esters of (meth)acrylic acid    (cf. monomers a2).

Each of the abovementioned monomers (a1) to (a14), with the exception ofthe monomer (a3), can be polymerized alone with the monomers (B). Inaccordance with the invention, however, it is advantageous to use atleast two monomers (A), since by this means it is possible to vary theprofile of properties of the resulting copolymers very widely, in aparticularly advantageous manner, and to tailor said profile ofproperties very targetedly to the particular intended use of the primarydispersions of the invention or of the coating materials of theinvention.

Further examples of suitable monomers (A) are disclosed in the Germanpatent application DE-A-196 28 142, page 2, line 5 to page 3, line 7.

Preferably, the monomers (A) are selected so as to give (meth)acrylatecopolymers whose profile of properties is determined primarily by the(meth)acrylates described above. In that case it is preferred ascomonomer (A) to use vinylaromatic hydrocarbons (a9); especiallystyrene.

The second starting products, essential to the invention, for preparingthe primary dispersions and coating materials of the invention and forthe process of the invention is at least one olefinically unsaturatedmonomer (B) which is different than the above-described monomers (A).

The olefinically unsaturated monomer (B) for use in accordance with theinvention has the general formula IR¹R²C═CR³R⁴  (I)

In the general formula I, the radicals R¹, R², R³ and R⁴ eachindependently of one another are hydrogen atoms or substituted orunsubstituted alkyl, cycloalkyl, alkylcycloalkyl, cycloalkylalkyl, aryl,alkylaryl, cycloalkylaryl arylalkyl or arylcycloalkyl radicals, with theproviso that at least two of the variables R¹, R², R³ and R⁴ aresubstituted or unsubstituted aryl, arylalkyl or arylcycloalkyl radicals,especially substituted or unsubstituted aryl radicals.

Examples of suitable alkyl radicals are methyl, ethyl, propyl,isopropyl, n-butyl, isobutyl, tert-butyl, amyl, hexyl or 2-ethylhexyl.

Examples of suitable cycloalkyl radicals are cyclobutyl, cyclopentyl orcyclohexyl.

Examples of suitable alkylcycloalkyl radicals are methylenecyclohexane,ethylenecyclohexane or propane-1,3-diylcyclohexane.

Examples of suitable cycloalkylalkyl radicals are 2-, 3- or 4-methyl-,-ethyl-, -propyl- or -butylcyclohex-1-yl.

Examples of suitable aryl radicals are phenyl, naphthyl or biphenylyl,preferably phenyl and naphthyl, and especially phenyl.

Examples of suitable alkylaryl radicals are benzyl or ethylene- orpropane-1,3-diylbenzene.

Examples of suitable cycloalkylaryl radicals are 2-, 3- or4-phenylcyclohex-1-yl.

Examples of suitable arylalkyl radicals are 2-, 3- or 4-methyl-,-ethyl-, -propyl- or -butylphen-1-yl.

Examples of suitable arylcycloalkyl radicals are 2-, 3- or4-cyclohexylphen-1-yl.

The above-described radicals R¹, R², R³ and R⁴ may be substituted. Forthis purpose it is possible to use electron-withdrawing orelectron-donating atoms or organic radicals.

Examples of suitable substituents are halogen atoms, especially chorineand fluorine, nitrile groups, nitro groups, partially or fullyhalogenated, especially chlorinated and/or fluorinated, alkyl,cycloalkyl, alkylcycloalkyl, cycloalkylalkyl, aryl, alkylaryl,cycloalkylaryl arylalkyl and arylcycloalkyl radicals, including thoseexemplified above, especially tert-butyl; aryloxy, alkyloxy andcycloalkyloxy radicals, especially phenoxy, naphthoxy, methoxy, ethoxy,propoxy, butyloxy or cyclohexyloxy; arylthio, alkylthio andcycloalkylthio radicals, especially phenylthio, naphthylthio,methylthio, ethylthio, propylthio, butylthio or cyclohexylthio; hydroxylgroups; and/or primary, secondary and/or tertiary amino groups,especially amino, N-methylamino, N-ethylamino, N-propylamino,N-phenylamino, N-cyclohexylamino, N,N-dimethylamino, N,N-diethylamino,N,N-dipropylamino, N,N-diphenylamino, N,N-dicyclohexylamino,N-cyclohexyl-N-methylamino or N-ethyl-N-methylamino.

Examples of monomers (B) used with particular preference in accordancewith the invention are diphenylethylene, dinaphthaleneethylene, cis- ortrans-stilbene, vinylidenebis(4-N,N-dimethylaminobenzene),vinylidenebis(4-aminobenzene) or vinylidenebis(4-nitrobenzene).

In accordance with the invention, the monomers (B) may be usedindividually or as a mixture of at least two monomers (B).

The proportion of the monomers (B) in the monomer mixture (A) and (B),based in each case on the mixture, is preferably from 0.01 to 10%, morepreferably from 0.1 to 9.0%, with particular preference from 0.15 to8.0%, with very particular preference from 0.2 to 7.0%, and inparticular from 0.25 to 6.0% by weight.

As regards the reaction regime and the properties of the resultingcopolymers, especially the acrylate copolymers, diphenylethylene is ofvery particular advantage and is therefore used with very particularpreference in accordance with the invention.

The monomers (A) and (B) to be used in accordance with the invention arereacted with one another to form copolymers in the presence of at leastone water-soluble and/or oil-soluble initiator which forms freeradicals. Examples of initiators which can be used are: dialkylperoxides, such as di-tert-butyl peroxide or dicumyl peroxide;hydroperoxides, such as cumene hydroperoxide or tert-butylhydroperoxide; peresters, such as tert-butyl perbenzoate, tert-butylperpivalate, tert-butyl per-3,5,5-trimethylhexanoate or tert-butylper-2-ethylhexanoate; peroxodicarbonates; potassium, sodium or ammoniumperoxodisulfate; azo initiators, examples being azodinitriles such asazobisisobutyronitrile; C—C-cleaving initiators such as benzpinacolsilyl ethers; or a combination of a nonoxidizing initiator with hydrogenperoxide. Further examples of suitable initiators are described in theGerman patent application DE-A-196 28 142, page 3, line 49 to page 4,line 6. Combinations of these initiators may also be used.

It is preferred to add comparatively large amounts of free-radicalinitiator, the proportion of the initiator in the reaction mixturebeing, based in each case on the overall amount of the monomers (A) andof the initiator, with particular preference from 0.2 to 20% by weight,with very particular preference from 0.5 to 15% by weight, and inparticular from 1.0 to 10% by weight.

The weight ratio of initiator to the monomers (B) is preferably from 5:1to 1:20.

The monomers (A) and (B) are, in accordance with the invention,copolymerized in the presence of at least one hydrophobic crosslinkingagent. The hydrophobic crosslinking agents preferably contain theabove-described reactive functional groups which undergo crosslinkingreactions with the complementary reactive functional groups present inthe resultant copolymers.

Examples of especially suitable crosslinking agents (C) are blockedpolyisocyanates, tris(alkoxycarbonylamino)triazines or fully etherifiedamino resins.

Examples of suitable blocking agents for preparing the blockedpolyisocyanates (C) are the blocking agents known from the U.S. patentU.S. Pat. No. 4,444,954:

-   i) phenols such as phenol, cresol, xylenol, nitrophenol,    chlorophenol, ethylphenol, t-butylphenol, hydroxybenzoic acid,    esters of these acids, or 2,5-di-tert-butyl-4-hydroxytoluene;-   ii) lactams, such as ε-caprolactam, δ-valerolactam, γ-butyrolactam    or β-propiolactam;-   iii) active methylenic compounds, such as diethyl malonate, dimethyl    malonate, ethyl or methyl acetoacetate, or acetylacetone;-   iv) alcohols such as methanol, ethanol, n-propanol, isopropanol,    n-butanol, isobutanol, t-butanol, n-amyl alcohol, t-amyl alcohol,    lauryl alcohol, ethylene glycol monomethyl ether, ethylene glycol    monoethyl ether, ethylene glycol monobutyl ether, diethylene glycol    monomethyl ether, diethylene glycol monoethyl ether, propylene    glycol monomethyl ether, methoxymethanol, glycolic acid, glycolic    esters, lactic acid, lactic esters, methylolurea, methylolmelamine,    diacetone alcohol, ethylenechlorohydrin, ethylenebromohydrin,    1,3-dichloro-2-propanol, 1,4-cyclohexyldimethanol or    acetocyanohydrin;-   v) mercaptans such as butyl mercaptan, hexyl mercaptan, t-butyl    mercaptan, t-dodecyl mercaptan, 2-mercaptobenzothiazole, thiophenol,    methylthiophenol or ethylthiophenol;-   vi) acid amides such as acetoanilide, acetoanisidine amide,    acrylamide, methacrylamide, acetamide, stearamide or benzamide;-   vii) imides such as succinimide, phthalimide or maleimide;-   viii) amines such as diphenylamine, phenylnaphthylamine, xylidine,    N-phenylxylidine, carbazole, aniline, naphthylamine, butylamine,    dibutylamine or butylphenylamine;-   ix) imidazoles such as imidazole or 2-ethylimidazole;-   x) ureas such as urea, thiourea, ethyleneurea, ethylenethiourea or    1,3-diphenylurea;-   xi) carbamates such as phenyl N-phenylcarbamate or 2-oxazolidone;-   xii) imines such as ethyleneimine;-   xiii) oximes such as acetone oxime, formaldoxime, acetaldoxime,    acetoxime, methyl ethyl ketoxime, diisobutyl ketoxime, diacetyl    monoxime, benzophenone oxime or chlorohexanone oximes;-   xiv) salts of sulfurous acid such as sodium bisulfite or potassium    bisulfite;-   xv) hydroxamic esters such as benzyl methacrylohydroxamate (BMH) or    allyl methacrylohydroxamate; or-   xvi) substituted pyrazoles, especially dimethylpyrazole, or    triazoles; and also-   xvii) mixtures of these blocking agents, especially dimethylpyrazole    and triazoles, malonic esters and acetoacetic esters or    dimethylpyrazole and succinimide.

Examples of suitable organic polyisocyanates for blocking are inparticular the so-called paint polyisocyanates having isocyanate groupsattached to aliphatic, cycloaliphatic, araliphatic and/or aromaticstructures. Preference is given to polyisocyanates having from 2 to 5isocyanate groups per molecule and having viscosities of from 100 to10,000, preferably from 100 to 5000.

Further examples of suitable polyisocyanates for blocking are describedin “Methoden der organischen Chemie”, Houben-Weyl, Volume 14/2, 4^(th)edition, Georg Thieme Verlag, Stuttgart 1963, pages 61 to 70, and by W.Siefken, Liebigs Annalen der Chemie, Volume 562, pages 75 to 136.Examples of those suitable are the polyurethane prepolymers containingisocyanate groups, which can be prepared by reacting polyols with anexcess of polyisocyanates and which are preferably of low viscosity.

Further examples of suitable polyisocyanates for blocking arepolyisocyanates containing isocyanurate, biuret, allophanate,iminooxadiazinedione, urethane, urea and/or uretdione groups.Polyisocyanates containing urethane groups, for example, are prepared byreacting some of the isocyanate groups with polyols, such astrimethylolpropane and glycerol, for example. Preference is given to theuse of aliphatic or cycloaliphatic polyisocyanates, especiallyhexamethylene diisocyanate, dimerized and trimerized hexamethylenediisocyanate isophorone diisocyanate, dicyclohexyl-methane2,4′-diisocyanate; dicyclohexylmethane 4,4′-diisocyanate, diisocyanatesderived from dimeric fatty acids, as marketed under the commercialdesignation DDI 1410 by Henkel and described in patents WO 97/49745 andWO 97/49747, especially2-heptyl-3,4-bis(9-isocyanatononyl)-1-pentylcyclohexane; or 1,2-, 1,4-or 1,3-bis(isocyanatomethyl)cyclohexane, 1,2-, 1,4- or1,3-bis(2-isocyanatoeth-1-yl)cyclohexane,1,3-bis(3-isocyanatoprop-1-yl)cyclohexane or 1,2-, 1,4- or1,3-bis(4-isocyanatobut-1-yl)cyclohexane,1,8-diisocyanato-4-isocyanatomethyloctane,1,7-diisocyanato-4-isocyanatomethylheptane or1-isocyanato-2-(3-isocyanatopropyl)cyclohexane, or mixtures of thesepolyisocyanates.

Very particular preference is given to the use of mixtures ofpolyisocyanates containing uretdione and/or isocyanurate groups and/orallophanate groups based on hexamethylene diisocyanate, as are formed bycatalytic oligomerization of hexamethylene diisocyanate usingappropriate catalysts.

Examples of particularly highly suitable amino resins (C) are melamineresins, guanamine resins or urea resins. In this context it is possibleto use any amino resin that is suitable for clearcoats, or a mixture ofsuch amino resins. For further details refer to Römpp Lexikon Lacke undDruckfarben, Georg Thieme Verlag, 1998, page 29, “Amino resins”, and thetextbook “Lackadditive” by Johan Bieleman, Wiley-VCH, Weinheim, N.Y.,1998, pages 242 ff., or to the book “Paints, Coatings and Solvents”,second completely revised edition, editors: D. Stoye and W. Freitag,Wiley-VCH, Weinheim, N.Y., 1998, pages 80 ff. Also suitable are thecustomary and known amino resins some of whose methylol and/ormethoxymethyl groups have been defunctionalized by means of carbamate orallophanate groups. Crosslinking agents of this kind are described inthe patents U.S. Pat. No. 4,710,542 and EP-B-0 245 700 and also in thearticle by B. Singh and coworkers “Carbamylmethylated Melamines, NovelCrosslinkers for the Coatings Industry” in Advanced Organic CoatingsScience and Technology Series, 1991, Volume 13, pages 193 to 207.

The particularly highly suitable tris-(alkoxycarbonylamino)triazines hadthe following formula:

Examples of particularly highly suitabletris(alkoxycarbonylamino)triazines are described in the patents U.S.Pat. Nos. 4,939,213, 5,084,541 or EP-A-0 624 577. Use is made inparticular of the tris(methoxy-, tris(butoxy- and/ortris(2-ethylhexoxycarbonylamino)-triazines.

The methyl butyl mixed esters, the butyl 2-ethylhexyl mixed esters andthe butyl esters are of advantage. They have the advantage over thesimple methyl ester of better solubility in polymer melts and also havea lower tendency to crystallize out.

Of the crosslinking agents (C) described above, the blockedpolyisocyanates offer particular advantages and are therefore used withvery particular preference in accordance with the invention.

In the process of the invention, the ratio of the monomers (A)comprising complementary reactive functional groups to the crosslinkingagents (C) may vary very widely. In accordance with the invention it isof advantage if the molar ratio of complementary reactive functionalgroups in (A) to complementary reactive functional groups in (C) is from5.0:1.0 to 1.0:5.0, preferably from 4.0:1.0 to 1.0:4.0, with particularpreference from 3.0:1.0 to 1.0:3.0, and in particular from 2.0:1 to1:2.0. Particular advantages result if the molar ratio is approximatelyor precisely 1.0:1.0.

In addition to the hydrophobic crosslinking agents (C) for use inaccordance with the invention and described above, the copolymerizationof the monomers (A) and (B) to be used in accordance with the inventionmay also be accompanied by hydrophobic compounds (D) which differ from(C). These hydrophobic compounds (D) are also referred to by those inthe art as costabilizers.

The hydrophobic compounds (D) comprise water-insoluble polymers,oligomers or substances of low molecular mass. Examples of suitablehydrophobic compounds (D) are esters of alpha,beta-monoolefinicallyunsaturated carboxylic acids, having 3 to 6 carbon atoms, with alcoholshaving 12 to 30 carbon atoms in the alkyl radical; esters of vinylalcohol and/or allyl alcohol with alkanemonocarboxylic, -sulfonic and/or-phosphonic acids having 12 to 30 carbon atoms in the molecule; amidesof alpha,beta-monoolefinically unsaturated carboxylic acids having 3 to6 carbon atoms with alkylamines having 12 to 30 carbon atoms in thealkyl radical; macromonomers based on olefinically unsaturated compoundshaving on average at least one olefinically unsaturated group, inparticular at least one terminal olefinically unsaturated group, in themolecule; polysiloxane macromonomers having on average at least oneolefinically unsaturated group, in particular at least one terminalolefinically unsaturated group, in the molecule; oligomeric and/orpolymeric products of addition polymerization, polycondensation and/orpolyaddition; water-insoluble molecular weight regulators, especiallymercaptans; aliphatic, cycloaliphatic and/or aromatic halogenated and/ornonhalogenated hydrocarbons; alkanols and/or alkylamines having at least12 carbon atoms in the alkyl radical; organosilanes and/ororganosiloxanes; vegetable, animal, semisynthetic and/or synthetic oils;hydrophobic dyes. Further examples of suitable hydrophobic compounds (D)or costabilizers (D), and the amounts in which they are advantageouslyused, are disclosed in the German patent application DE-A-196 28 142,page 4, lines 37 to 59.

The monomers (A) and (B) for use in accordance with the invention mayfurther be copolymerized in the presence of emulsifiers and/orprotective colloids (E). Examples of suitable emulsifiers and/orprotective colloids (E), and the amounts in which they areadvantageously used, are disclosed in the German patent applicationDE-A-196 28 142, page 3, lines 8 to 48.

In terms of the molecular weight distribution, the copolymer formed fromthe comonomers (A) and (B) is not subject to any restrictionswhatsoever. Advantageously, however, the copolymerization is conductedso as to result in a molecular weight distribution Mw/Mn, measured bygel permeation chromatography using polystyrene as standard, of≦12, withparticular preference≦10, and in particular≦7. The molecular weights ofthe constituents (A) are controllable within wide ranges by the choiceof the ratio of monomer (A) to monomer (B) to free-radical initiator. Inthis relationship, the amount of monomer (B) is a particular determinantof the molecular weight, specifically such that the higher the fractionof monomer (B) the lower the molecular weight obtained.

Suitable reactors for the copolymerization processes are the customaryand known stirred vessels, cascades of stirred vessels, tube reactors,loop reactors or Taylor reactors, as described, for example, in thepatents DE-B-1 071 241, EP-A-0 498 583 or in the article by K. Kataokain Chemical Engineering Science, Volume 50, No. 9, 1995, pages 1409 to1416. The free-radical copolymerization is preferably conducted instirred vessels or Taylor reactors, the Taylor reactors being configuredsuch that the conditions of Taylor flow are met over the entire lengthof the reactor, even if the kinematic viscosity of the reaction mediumalters greatly—in particular, increases—as a result of thecopolymerization.

In accordance with the invention, the copolymerization is conducted inan aqueous medium.

The aqueous medium contains essentially water. Besides the crosslinkingagents (C) described in detail above and also any hydrophobic compounds(D) and/or emulsifiers and/or protective colloids (E) the aqueous mediummay comprise customary and known coatings additives (F) and/or otherdissolved solid, liquid or gaseous, organic and/or inorganic substancesof low and/or high molecular mass, provided these do not adverselyaffect, let alone inhibit, the copolymerization. For the purposes of thepresent invention, the term “minor amount” means an amount which doesnot destroy the aqueous nature of the aqueous medium.

Alternatively, the aqueous medium may simply consist of water.

The copolymerization is advantageously conducted at temperatures aboveroom temperature, preference being given to the choice of a temperaturerange of from 30 to 95° C., with very particular preference from 50 to90° C.

When using particularly volatile monomers (A) and/or (B) thecopolymerization may also be conducted under pressure, preferably underfrom 1.5 to 3000 bar, with particular preference from 5 to 1500 and, inparticular, from 10 to 1000 bar. In specific cases, temperatures higherthan 95° C. may be used here.

It proves here to be a particular advantage of the process of theinvention that it can also be conducted in batch mode. Otherwise, usemay also be made of the regimes described in the German patentapplication DE-A-196 28 142, page 4, lines 6 to 36.

In accordance with the invention, the copolymerization is conducted in amicroemulsion or miniemulsion, in particular a miniemulsion. In thiscase the average particle diameter of the emulsified monomer droplets isbelow 500 nm. It is preferably from 10 to 500 nm, more preferably from50 to 400 nm, and with very particular preference from 100 to 350 nm.The particle diameter is the so-called z-average particle diameter,which is determined by means of photon correlation spectroscopy inaccordance with the principle of dynamic, quasielastic light scattering.For this purpose use may be made, for example, of a Coulter N4 PlusParticle Analyzer from Coulter Scientific Instruments or a PCS MalvernZetasizer 1000. The measurement is normally made on an aqueous emulsioncontaining 0.01% by weight of the emulsified monomer droplets. Theaqueous emulsion further comprises, in the aqueous phase, thecorresponding monomers in dissolved form (up to saturation), so that theemulsified monomer droplets do not break up.

The process of the invention may be performed so as to give the bimodalparticle size distribution described above. Methods of producing bimodalparticle size distributions are customary and known in the technologicalfield in question here. It is preferred to use the seed method describedin the German patent application DE-A-196 28 142, page 5, lines 31 to49.

The preparation of the miniemulsion as part of the process of theinvention has no particular features as to method, but instead takesplace in accordance with the customary and known methods of dispersingor emulsifying in a high shear field. Examples of suitable methods aredescribed in the patents DE-A-196 28 142, page 5, lines 10 to 30,DE-A-196 28 143, page 7, lines 30 to 58, or EP-A-0 401 565, [lacuna]lines 27 to 51.

An essential advantage of the primary dispersions of the invention isthat they can be used per se as coating materials of the invention,preferably as surfacers, solid-color topcoat, aqueous basecoat andclearcoat materials, in particular as clearcoat materials. For these enduses, at least one customary and known coatings additive (F) ineffective amounts may be added to the primary dispersions of theinvention before, during and/or after their preparation. Before orduring the preparation of the primary dispersions of the invention, theonly coatings additives (F) added are those which do not disrupt, oreven totally inhibit, the miniemulsion polymerization. The generaltechnical knowledge of the skilled worker allows him or her to identifysuch additives (F). Preferably, said additives (F) are added after thepreparation of the primary dispersions of the invention.

Examples of suitable coatings additives (F) are pigments, as describedin Römpp Lexikon Lacke und Druckfarben, Georg Thieme Verlag, 1998, pages176, “Effect pigments”; pages 380 and 381 “Metal oxide-mica pigments” to“Metal pigments”; pages 180 and 181, “Iron blue pigments” to “Black ironoxide”; pages 451 to 453, “Pigments” to “Pigment volume concentration”;page 563, “Thioindigo pigments”; and page 567, “Titanium dioxidepigments”. These additives (F) are used when the coating materials ofthe invention are used as surfacers, solid-color topcoats or aqueousbasecoats, but in particular as aqueous basecoats in the context of theso-called wet-on-wet technique (cf., for example, European patent 0 089497), to produce multicoat color and/or effect paint systems.

Further examples of suitable coatings additives (F), which may be usedboth in the pigmented paints and in the unpigmented coating materials,are oligomeric and polymeric, thermally curable, linear and/or branchedpoly(meth)acrylates or acrylate copolymers of block, comb and/or randomstructure, especially those described in the patent DE-A-197 36 535,polyesters, especially those described in the patents DE-A-40 09 858 orDE-A-44 37 535, alkyds, acrylated polyesters, polylactones,polycarbonates, polyethers, epoxy resinamine adducts, (meth)acrylatediols, partially hydrolyzed polyvinyl esters, polyurethanes andacrylated polyurethanes, as described in the patents EP-A-0 521 928,EP-A-0 522 420, EP-A-0 522 419, EP-A-0 730 613 or DE-A-44 37 535, orpolyureas.

Further examples of suitable coatings additives (F) are organic andinorganic fillers, thermally curable reactive diluents, low-boilingand/or high-boiling organic solvents (“long solvents”), UV absorbers,light stabilizers, free-radical scavengers, thermally labilefree-radical initiators, crosslinking catalysts, devolatilizers, slipadditives, polymerization inhibitors, defoamers, emulsifiers, wettingagents, adhesion promoters, leveling agents, film-forming auxiliaries,rheology control additives, or flame retardants. Further examples ofsuitable coatings additives are described in the textbook “Lackadditive”by Johan Bieleman, Wiley-VCH, Weinheim, N.Y., 1998.

If the coating materials of the invention are to be curable with actinicradiation as well (dual cure), they comprise additives (F) curable withactinic radiation. Said actinic radiation may comprise electromagneticradiation such as near infrared (NIR), visible light, UV light orX-rays, or corpuscular radiation such as electron beams. Examples ofsuitable additives (F) curable with actinic radiation are known fromGerman patent DE-C-197 09 467.

In terms of method, the application of the coating materials of theinvention has no special features, but instead can be carried out by allcustomary application methods, such as spraying, knife coating,brushing, flow coating, dipping, trickle coating or roller coating, forexample. It is preferred to use spray application methods, such as, forexample, compressed air spraying, airless spraying, high-speed rotation,electrostatic spray application (ESTA), alone or in conjunction with hotspray application such as hot air spraying, for example.

Suitable coating substrates are all surfaces which are not damaged bycuring of the coatings present on them with application of heat;examples include metals, plastics, wood, ceramic, stone, textile, fibercomposites, leather, glass, glass fibers, glasswool and rockwool,mineral-bound and resin-bound building materials, such as plasterboardand cement slabs or roof shingles, and also assemblies of thesematerials. Accordingly, the coating material of the invention is alsosuitable for applications outside of automotive finishing, especially inthe coating of furniture and in industrial coating, including coilcoating, container coating and the impregnation or coating of electricalcomponents. In the context of industrial coatings, it is suitable forcoating virtually all parts for private or industrial use, such asradiators, domestic appliances, small metal parts such as nuts andbolts, hub caps, wheel rims, packaging, or electrical components such asmotor windings or transformer windings.

In the case of electrically conductive substrates it is possible to useprimers produced in a customary and known manner from electrodeposition(ED) coating materials. Suitable for this purpose are both anodic (AED)and cathodic (CED) electrodeposition coating materials, but especiallyCED. Unfunctionalized and/or apolar plastic surfaces can be subjected toconventional pretreatment before coating, such as with a plasma or byflaming, or may be provided with an aqueous primer.

The method of curing the applied coating materials of the invention alsohas no special features, but instead takes place in accordance with thecustomary and known thermal methods such as heating in a circulating airoven or irradiation with IR lamps, which in the case of dual cure may besupplemented by exposure to actinic radiation. In this context it ispossible to use radiation sources such as high-pressure or low-pressuremercury vapor lamps, which may be doped with lead in order to open up aradiation window up to 405 nm, or electron beam sources.

The resultant coatings of the invention, especially the single-coat ormulticoat color and/or effect paint systems and clearcoat systems of theinvention, are easy to produce and have outstanding optical propertiesand very high chemical resistance and weathering stability. Accordingly,the substrates of the invention, comprising at least one coating of theinvention, are also of particularly high service value and have aparticularly long service life, which makes them particularlyattractive, economically and technically, for producers and users.

EXAMPLES Examples 1 to 4

The preparation of primary dispersions of the invention and of coatingmaterials of the invention by the process of the invention

For carrying out Examples 1 to 4, first of all an emulsifier wasdissolved in water. Then olefinically unsaturated monomers (A),diphenylethylene (B), a blocked polyisocyanate (C), and an oil-solubleinitiator were mixed with one another. The resultant organic solutionwas converted into a milky emulsion using an Ultraturrax at roomtemperature over the course of 4 seconds. The resultant preemulsionswere stable for several minutes, i.e., they did not exhibit phaseseparation and hence could be processed further to finely dividedminiemulsions without problems by means of a high-pressure homogenizingapparatus. For preparing the miniemulsions of Examples 1 to 4 theindividual preemulsions were introduced into the storage vessel of apressure release homogenizer and were emulsified under maximum pressurein circulation mode with cooling for 1 minutes. Followingemulsification, the miniemulsions of Examples 1 to 4 had particle sizesin the range from 100 nm to 500 nm and contained 40% by weight ofmonomer mixture and polyisocyanate (100%), based on the total amount ofthe respective miniemulsion, and were stable on storage for severalweeks.

Table 1 gives an overview of the starting products used for theminiemulsions of Examples 1 to 4, the amounts in which they were used,and the z-average particle diameters of the monomer droplets, which weredetermined by means of photon correlation spectroscopy in accordancewith the principle of dynamic, quasielastic light scattering.

The miniemulsions of Examples 1 to 4 were transferred to suitable steelreactors and heated slowly with stirring at from 80 to 90° C. Theminiemulsions were stirred at this temperature until the solids contentof the resultant primary dispersions 1 to 4 of the invention no longerrose. The primary dispersions of the invention were sedimentation-stablefor several weeks.

Table 1 gives an overview of the polymerization period, the theoreticalglass transition temperature Tg, calculated by the method of Fox, of thecopolymers present in the primary dispersions of the invention, theirhydroxyl number, their molecular weight and their polydispersity of themolecular weight distribution, and also the z-average particle diametersand the solids contents and pH values of the primary dispersions of theinvention.

The z-average particle diameters of the miniemulsions 1 to 4 and of theprimary dispersions 1 to 4 of the invention were measured using a PCSMalvern Zetasizer 1000.

The primary dispersions of the invention from Examples 1 to 4 were knifecoated onto glass plates at a wet film thickness of 150 μm and werebaked for 30 minutes at 145° C., 160° C. and 180° C.

Table 1 gives an overview of important performance properties of theresultant clearcoats of the invention from Examples 1 to 4.

The results demonstrate that the clearcoats of the invention have a highsolvent stability, a high gloss, and a smooth surface.

TABLE 1 Material composition and properties of the miniemulsions 1 to 4of the invention, polymerization conditions, material composition andproperties of the primary dispersions 1 to 4 of the invention, andimportant performance properties of the clearcoats 1 to 4 of theinvention Example 1 2 3 4 Miniemulsion: Composition (parts by weight):Emulsifier^(a)) 0.521 0.521 0.521 0.521 Methyl methacrylate 16.95 16.9516.95 16.95 n-Butyl methacrylate 13.69 13.69 13.69 13.69 Styrene 15.3214.99 14.34 13.04 Hydroxypropyl methacrylate 18.25 18.25 18.25 18.25Diphenylethylene 0.978 1.3 1.955 3.264 Blocked polyisocyanate^(b)) 34.2934.29 34.29 34.29 OH:NCO ratio 1:1 1:1 1:1 1:1 Particle diameter (nm)151 144 153 151 Polymerization: Initiator^(c)) (parts by weight per 100parts by weight of emulsifier, monomer mixture and blockedpolyisocyanate) 3.26 3.26 3.26 3.26 Polymerization time (h) 10.5 7.017.5 11.0 Primary dispersion: Solids content^(d)) (% by weight) 37.936.2 35.7 34.7 Particle diameter (nm) 143 154 154 153 pH 6.0 6.0 6.0 6.0Sediment wet (g) 0 0 0 0 Copolymer: Number-average molecular 19.30014.880 11.550 8.787 weight Mn^(e)) (daltons) Mass-average molecular110.600 80.490 59.150 44.660 weight Mw^(e)) (daltons) PolydispersityMw/Mn 5.73 5.41 5.18 5.08 Class transition temperature 74.55 74.55 74.5574.55 (theoretical according to Fox) (° C.) Hydroxyl number (mg KOH/g)109 109 109 109 Clearcoat: MEK-DR^(f)) (145/160/180° C.) 3/190/ 5/45/3/90/ 1/74/ >200 >200 >200 >200 Gloss (visual) high high high highSurface texture^(g)) (visual) 2 1 1 1 ^(a)) Sodium lauryl sulfate,Texapon ® from Henkel; ^(b)) Dimethylpyrazole-blocked commercialpolyisocyanate; ^(c)) tert-Butyl peroxyethylhexanoate; ^(d)) 130° C.,one hour; ^(e)) Measured by gel permeation chromatography usingpolystyrene as internal standard; ^(f)) Number of double rubs with acotton pad soaked with methyl ethyl ketone; ^(g)) Rating: 1 = good, 2 =satisfactory, 3 = poor;

Examples 5 and 6

The preparation of primary dispersions of the invention and productionof clearcoats of the invention by the process of the invention

For carrying out Examples 5 and 6, the process of Example 2 was repeatedbut using the water-soluble initiator ammonium peroxodisulfate insteadof the oil-soluble initiator tert-butyl peroxyethylhexanoate.Additionally, in Example 5, the miniemulsion and the 24% strengthaqueous ammonium peroxodisulfate solution were metered in as twoseparate feed streams simultaneously over a period of two hours.Additionally, in Example 6, the miniemulsion was introduced as initialcharge at 80° C. and stirred, and the 24% strength ammoniumperoxodisulfate solution was added dropwise at a uniform rate over thecourse of two hours. The miniemulsions 5 and 6 contained 35% by weightof monomer mixture and polyisocyanate (100%), based on the total amountof the respective miniemulsion, and were stable on storage for severalweeks.

Table 2 gives an overview of the starting products and their amounts andalso the results of the experiments.

TABLE 2 Material composition and properties of the miniemulsions 5 and 6of the invention, polymerization conditions, material composition andproperties of the primary dispersions 5 and 6 of the invention, andimportant performance properties of the clearcoats 5 and 6 of theinvention Example 5 6 Miniemulsion: Composition (parts by weight):Emulsifier^(a)) 0.2 0.2 Methyl methacrylate 17.0 17.0 n-Butylmethacrylate 13.73 13.73 Styrene 15.04 15.04 Hydroxypropyl methacrylate18.31 18.31 Diphenylethylene 1.31 1.31 Blocked polyisocyanate^(b)) 34.434.4 OH:NCO ratio 1:1 1:1 Particle diameter (nm) 210 210 Polymerization:Initiator^(c)) (parts by weight per 100 parts by weight of emulsifier,monomer mixture and blocked polyisocyanate) 1.96 1.96 Polymerizationtime (h) 4.0 3.0 Primary dispersion: Solids content^(d)) (% by weight)32.7 34.4 Particle diameter (nm) 273 314 pH 3.6 3.1 Copolymer:Number-average molecular weight Mn^(e)) (daltons) 11.740 12.020Mass-average molecular weight Mw^(e)) (daltons) 19.830 20.660Polydispersity Mw/Mn 1.69 1.72 Glass transition temperature 74.55 74.55(theoretical according to Fox) (° C.) Hydroxyl number (mg KOH/g) 109 109Clearcoat: MEK-DR^(f)) (145/160/180° C.) 78/200/ 81/200/ >200 >200Surface texture^(g)) (visual) 2 2 ^(a)) Sodium lauryl sulfate, Texapon ®from Henkel; ^(b)) Dimethylpyrazole blocked commercial polyisocyanate;^(c)) 100% strength ammonium peroxodisulfate; ^(d)) 130° C., one hour;^(e)) Measured by gel permeation chromatography using polystyrene asinternal standard; ^(f)) Number of double rubs with a cotton pad soakedwith methyl ethyl ketone; ^(g)) Rating: 1 = good, 2 = satisfactory, 3 =poor;

The results demonstrate the particularly high solvent resistance of theclearcoats 5 and 6 of the invention.

1. An aqueous composition comprising a polymer having a diameter ≦500 nmcomprising a controlled free-radical microemulsion or miniemulsionpolymerization product of A) at least one olefinically unsaturatedmonomer and B) at least one olefinically unsaturated monomer that isdifferent than the olefinically unsaturated monomer (A) and has thegeneral formula IR¹R²C═CR³R⁴  (I) wherein R¹, R², R³, and R⁴ are each independently oneof a hydrogen atom, an unsubstituted alkyl radical, an unsubstitutedcycloalkyl radical, an unsubstituted alkylcycloalkyl radical, anunsubstituted cycloalkylalkyl radical, an unsubstituted aryl radical, anunsubstituted alkylaryl radical, an unsubstituted cycloalkylarylradical, an unsubstituted arylalkyl radical, an unsubstitutedarylcycloalkyl radical, a substituted alkyl radical, a substitutedcycloalkyl radical, a substituted alkylcycloalkyl radical, a substitutedcycloalkylalkyl radical, a substituted aryl radical, a substitutedalkylaryl radical, a substituted cycloalkylaryl radical, a substitutedarylalkyl radical, and a substituted arylcycloalkyl radical, with theproviso that at least two of R¹, R², R³, and R⁴ are at least one of anunsubstituted aryl radical, an unsubstituted arylalkyl radical, anunsubstituted arylcycloalkyl radical, a substituted aryl radical, asubstituted arylalkyl radical, and a substituted arylcycloalkyl radical;in the presence of at least C) at least one hydrophobic crosslinkingagent for the polymerization product of (A) and (B); wherein the aqueouscomposition is one of a primary dispersion and a coating material, andwherein the polymer is at least one of a dispersed solid polymerparticle, an emulsified solid polymer particle, a dispersed liquidpolymer particle, an emulsified liquid polymer particle, and a dispersedsolid core-shell particle.
 2. The aqueous composition of claim 1,wherein the aryl radical is one of a phenyl radical and a naphthylradical.
 3. The aqueous composition of claim 1, wherein the substituentin at least one of R¹, R², R³, and R⁴ is one of an electron-withdrawingatom, an electron-donating atom, and an organic radical.
 4. The aqueouscomposition of claim 3, wherein the substituent is at least one of ahalogen atom, a nitrile, a nitro group, an at least partiallyhalogenated alkyl radical, an at least partially halogenated cycloalkylradical, an at least partially halogenated alkylcycloalkyl radical, anat least partially halogenated cycloalkylalkyl radical, an at leastpartially halogenated aryl radical, an at least partially halogenatedalkylaryl radical, an at least partially halogenated cycloalkylarylradical, an at least partially halogenated arylalkyl radical, and an atleast partially halogenated arylcycloalkyl radical, an aryloxy radical,a alkyloxy radical, and a cycloalkyloxy radical, an arylthio radical, aalkylthio radical, a cycloalkylthio radical, a primary amino group, asecondary amino group, and a tertiary amino group.
 5. The aqueouscomposition of claim 1, wherein the crosslinking agent is at least oneof a blocked polyisocyanate, a tris(alkoxycarbonylamino)triazine, and afully etherified amino resin.
 6. The aqueous composition of claim 1,wherein the monomers (A) and (B) are copolymerized in the presence of atleast one further hydrophobic compound (D) other than the crosslinkingagent (C).
 7. The aqueous composition of claim 6, wherein the furtherhydrophobic compound is water-insoluble and is one of a polymer, anoligomer, and a substances of low molecular mass.
 8. The aqueouscomposition of claim 7, wherein the further hydrophobic compound is atleast one of: i) an ester of an α,β-monoolefinically unsaturatedcarboxylic acid, having 3 to 6 carbon atoms, with an alcohol having 12to 30 carbon atoms in the alkyl radical; ii) an ester of a) at least oneof a vinyl alcohol and an allyl alcohol with b) at least one of analkanemonocarboxylic acid, an alkanemonosulfonic acid, and analkanemonophosphonic acid having 12 to 30 carbon atoms in the molecule;iii) an amide of an α,β-monoolefinically unsaturated carboxylic acidhaving 3 to 6 carbon atoms with an alkylamine having 12 to 30 carbonatoms in the alkyl radical; iv) a macromonomer comprising anolefinically unsaturated compound having on average at least oneolefinically unsaturated group in the molecule; v) a polysiloxanemacromonomer having on average at least one olefinically unsaturatedgroup in the molecule; vi) at least one of an oligomeric reactionproduct and a polymeric reaction product of at least one of additionpolymerization, polycondensation, and polyaddition; vii) awater-insoluble molecular weight regulator; viii) at least one of analkanol and an alkylamine having at least 12 carbon atoms in the alkylradical; ix) at least one of an organosilane and an organosiloxane; x)at least one of a vegetable oil, an animal oil, a semisynthetic oil, anda synthetic oil; and xi) a hydrophobic dye.
 9. The aqueous compositionof claim 1, wherein the monomers (A) and (B) are copolymerized in thepresence of at least one of an emulsifier and a protective colloid. 10.The aqueous composition of claim 1, wherein monomer (A) is at least oneof: a1) a (meth)acrylic ester; a2) a monomer that carries per moleculeat least one hydroxyl group; a3) a monomer that carries per molecule atleast one acid group that can be converted into a corresponding acidanion group; a4) a vinyl ester of an alpha-branched monocarboxylic acidhaving 5 to 18 carbon atoms in the molecule; a5) a reaction product of a(meth)acrylic acid with a glycidyl ester of an alpha-branchedmonocarboxylic acid having from 5 to 18 carbon atoms per molecule; a6)at least one of a cyclic olefin and an acyclic olefin; a7) a(meth)acrylamide; a8) a monomer containing at least one epoxide group;a9) a vinylaromatic hydrocarbon; a10) a nitrile; a11) a vinyl compound;a12) an allyl compound; a13) a polysiloxane macromonomer having anumber-average molecular weight Mn of from 1,000 to 40,000 andcontaining on average from 0.5 to 2.5 ethylenically unsaturated doublebonds per molecule; and a14) an acryloyloxysilane-containing vinylmonomer comprising a reaction product of a material and at least one ofmethacrylic acid and a hydroxyalkyl ester of (meth)acrylic acid, whereinthe material comprises a reaction product of a hydroxy-functional silaneand epichlorohydrin; with the proviso that the monomer (a3) is not usedas the sole monomer (A).
 11. The aqueous composition of claim 1, whereinat least one monomer (A) contains reactive functional groups that areable to undergo a crosslinking reaction with a complementary reactivefunctional group of the crosslinking agent (C).
 12. The aqueouscomposition of claim 1, wherein the controlled free-radicalmicroemulsion or miniemulsion polymerization is initiated by aninitiator that forms free radicals and is at least one of water-solubleand oil-soluble.
 13. The aqueous composition of claim 1, wherein thedispersed core-shell particles comprise cores of organic solids andshells of polymers that contain in copolymerized form at least onemonomer (A) and at least one monomer (B).
 14. The aqueous primarycomposition of claim 1, wherein the cores of the core-shell particlesare prepared by one of free-radical microemulsion polymerization andminiemulsion free-radical polymerization.
 15. The aqueous composition ofclaim 1, wherein the composition further comprises at least one coatingsadditive.
 16. The aqueous composition of claim 1, wherein thecomposition further comprises a constituent that can be cured withactinic radiation.
 17. A process for preparing the aqueous compositionof claim 1 comprising controlled free-radical microemulsion orminiemulsion polymerizing monomer (A) and monomer (B) in the presence ofat least one hydrophobic crosslinking agent (C) for the polymerizationproduct of (A) and (B).
 18. The process of claim 17, wherein the arylradical is one of a phenyl radical and a naphthyl radical.
 19. Theprocess of claim 17, wherein the substituent in at least one of R¹, R²,R³, and R⁴ is one of an electron-withdrawing atom, an electron-donatingatom, and an organic radical.
 20. The process of claim 19, wherein thesubstituent is at least one of a halogen atom, a nitrile, a nitro group,an at least partially halogenated alkyl radical, an at least partiallyhalogenated cycloalkyl radical, an at least partially halogenatedalkylcycloalkyl radical, an at least partially halogenatedcycloalkylalkyl radical, an at least partially halogenated aryl radical,an at least partially halogenated alkylaryl radical, an at leastpartially halogenated cycloalkylaryl radical, an at least partiallyhalogenated arylalkyl radical, and an at least partially halogenatedarylcycloalkyl radical, an aryloxy radical, a alkyloxy radical, and acycloalkyloxy radical, an arylthio radical, a alkylthio radical, acycloalkylthio radical, a primary amino group, a secondary amino group,and a tertiary amino group.
 21. The process of claim 17, wherein thecrosslinking agent is at least one of a blocked polyisocyanate, atris(alkoxycarbonylamino)triazine, and a fully etherified amino resin.22. The process of claim 17, wherein the monomers (A) and (B) arecopolymerized in the presence of at least one further hydrophobiccompound (D) other than the crosslinking agent (C).
 23. The process ofclaim 22, wherein the further hydrophobic compound is water-insolubleand is one of a polymer, an oligomer, and a substances of low molecularmass.
 24. The process of claim 23, wherein the further hydrophobiccompound is at least one of: i) an ester of an α,β-monoolefinicallyunsaturated carboxylic acid, having 3 to 6 carbon atoms, with an alcoholhaving 12 to 30 carbon atoms in the alkyl radical; ii) an ester of a) atleast one of a vinyl alcohol and an allyl alcohol with b) at least oneof an alkanemonocarboxylic acid, an alkanemonosulfonic acid, and analkanemonophosphonic acid having 12 to 30 carbon atoms in the molecule;iii) an amide of an α,β-monoolefinically unsaturated carboxylic acidhaving 3 to 6 carbon atoms with an alkylamine having 12 to 30 carbonatoms in the alkyl radical; iv) a macromonomer comprising anolefinically unsaturated compound having on average at least oneolefinically unsaturated group in the molecule; v) a polysiloxanemacromonomer having on average at least one olefinically unsaturatedgroup in the molecule; vi) at least one of an oligomeric reactionproduct and a polymeric reaction product of at least one of additionpolymerization, polycondensation, and polyaddition; vii) awater-insoluble molecular weight regulator; viii) at least one of analkanol and an alkylamine having at least 12 carbon atoms in the alkylradical; ix) at least one of an organosilane and an organosiloxane; x)at least one of a vegetable oil, an animal oil, a semisynthetic oil, anda synthetic oil; and xi) a hydrophobic dye.
 25. The process of claim 17,wherein the monomers (A) and (B) are copolymerized in the presence of atleast one of an emulsifier and a protective colloid.
 26. The process ofclaim 17, wherein monomer (A) is at least one of: a1) a (meth)acrylicester; a2) a monomer that carries per molecule at least one hydroxylgroup; a3) a monomer that carries per molecule at least one acid groupthat can be converted into a corresponding acid anion group; a4) a vinylester of an alpha-branched monocarboxylic acid having 5 to 18 carbonatoms in the molecule; a5) a reaction product of a (meth)acrylic acidwith a glycidyl ester of an alpha-branched monocarboxylic acid havingfrom 5 to 18 carbon atoms per molecule; a6) at least one of a cyclicolefin and an acyclic olefin; a7) a (meth)acrylamide; a8) a monomercontaining at least one epoxide group; a9) a vinylaromatic hydrocarbon;a10) a nitrile; a11) a vinyl compound; a12) an allyl compound; a13) apolysiloxane macromonomer having a number-average molecular weight Mn offrom 1,000 to 40,000 and containing on average from 0.5 to 2.5ethylenically unsaturated double bonds per molecule; and a14) anacryloyloxysilane-containing vinyl monomer comprising a reaction productof a material and at least one of methacrylic acid and a hydroxyalkylester of (meth)acrylic acid, wherein the material comprises a reactionproduct of a hydroxy-functional silane and epichlorohydrin; with theproviso that the monomer (a3) is not used as the sole monomer (A). 27.The process of claim 17, wherein at least one monomer (A) containsreactive functional groups that are able to undergo a crosslinkingreaction with a complementary reactive functional group of thecrosslinking agent (C).
 28. The process of claim 17, wherein thecontrolled free-radical microemulsion or miniemulsion polymerization isinitiated by an initiator that forms free radicals and is at least oneof water-soluble and oil-soluble.
 29. The process of claim 17, whereinthe dispersed core-shell particles comprise cores of organic solids andshells of polymers that contain in copolymerized form at least onemonomer (A) and at least one monomer (B).
 30. The process composition ofclaim 17, wherein the cores of the core-shell particles are prepared byone of free-radical microemulsion polymerization and miniemulsionfree-radical polymerization.
 31. The process of claim 17 furthercomprising adding at least one of a crosslinking agent, an additionalbinder, a coatings additive, and an additive that can be cured withactinic radiation.
 32. The process of claim 17 further comprisingapplying the aqueous composition to a substrate to provide one of anautomotive OEM finish, an automotive refinish, an industrial coating, acoil coating, a container coating, an electrical component coating, anda furniture coating.
 33. The process of claim 17 further comprisingforming at least one coat on a substrate, wherein the substrate is oneof primed and unprimed, and wherein the coat is at least one of aclearcoat, a color paint system, an effect paint system, and a color andeffect paint system.
 34. The substrate formed by the process of claim33.